Missing photos after switching Apple IDs

Hello, In 2014 I received and iPad Air that was logged into my older siblings Apple ID. In 2018 I purchased an iPhone and created my own Apple ID, earlier this year I decided to switch my siblings ID on my iPad to my personal ID. After doing so I went through my iPad and all of my old photos are gone and have been replaced with all of my photos on my iPhone and it gets every new one I take. Is there a way to restore my old photos? I haven’t switched back IDs because I’m scared I’ll do something wrong:(